"It feels great to be back in Brisbane," said Williams after a 6am arrival following a five-hour stopover in Dubai. "The foot is better. It is really good. It's come through fine."

Wozniacki, accompanied by boyfriend golfer Rory McIlroy, also looked in good touch as she blew out the cobwebs in her first day back on Australian soil.

The Danish former world No.1 sent the tongues of sharp-eyed fans wagging by wearing a flash sapphire and diamond ring before removing it as she hopped on to court.

Their sessions were in contrast to frustrated local hope Stosur's hour on court, two days out from the start of the Brisbane tournament, as she chided herself several times.

The world No.9 repeatedly found the net and was visibly angered by her practice form, uttering "C'mon Sam" and swinging her racquet in annoyance.

Despite winning the 2011 US Open and being entrenched in the world's top 10 for the past three years, Stosur has continually struggled to cope with expectations at home.

World No.8 and 2011 Wimbledon champion Petra Kvitova felt for the Gold Coaster who has never passed the second round in Brisbane nor made the quarter-finals at Melbourne Park.

"For Sam, it's hard to play here because she wants too much from herself and she's trying to fight with this and of course the people around are supporting her but it's not easy to play with all the pressure here and in the grand slam in Melbourne," the Czech said.

Kvitova had no doubt Williams was the player to beat in Brisbane and at the Australian Open.

"We see how she played last season and she had incredible results - she was for sure the best one," she said.

Williams was the player of 2012 on the WTA Tour after overcoming her worst-ever grand slam performance - a first-round loss at Roland Garros - to win Wimbledon, the Olympics, US Open and the WTA Championship.

"I definitely think I can improve some more," the 31-year-old, who now has 15 grand slam singles titles, said after crowning her season in style in Istanbul.

That's just three off the 18 collected by Martina Navratilova and Chris Evert, with only Steffi Graf's 22 and Australian Margaret Court's record 24 looking potentially out of reach.